In patients with suspected myocarditis, FDG-PET is in good agreement with CMR findings.

The objective of the present study was to evaluate whether integrated 18 F-FDG PET/MR imaging could improve the diagnostic workup in patients with cardiac masses. Methods: Twenty patients were prospectively assessed using integrated cardiac 18 F-FDG PET/MR imaging: 16 patients with cardiac masses of unknown identity and 4 patients with cardiac sarcoma after surgical therapy. All scans were obtained on an integrated 3-T PET/MR device. The MR protocol consisted of half Fourier acquisition single-shot turbo spin-echo sequence, cine, and T2-weighted images as well as T1-weighted images before and after injection of gadobutrol. PET data were acquired simultaneously with the MR scan after injection of 199 ± 58 MBq of 18 F-FDG. Patients were prepared with a high-fat, lowcarbohydrate diet in a period of 24 h before the examination, and 50 IU/kg of unfractionated heparin were administered intravenously 15 min before 18 F-FDG injection. Results: Cardiac masses were diagnosed as follows: metastases, 3; direct tumor infiltration via pulmonary vein, 1; local relapse of primary sarcoma after surgery, 2; Burkitt lymphoma, 1; scar/patch tissue after surgery of primary sarcoma, 2; myxoma, 4; fibroelastoma, 1; caseous calcification of mitral annulus, 3; and thrombus, 3. The maximum standardized uptake value (SUV max ) in malignant lesions was significantly higher than in nonmalignant cases (13.2 ± 6.2 vs. 2.3 ± 1.2, P 5 0.0004). When a threshold of 5.2 or greater was used, SUV max was found to yield 100% sensitivity and 92% specificity for the differentiation between malignant and nonmalignant cases. T2-weighted hyperintensity and contrast enhancement both yielded 100% sensitivity but a weak specificity of 54% and 46%, respectively. Morphologic tumor features as assessed by cine MR imaging yielded 86% sensitivity and 92% specificity. Consent interpretation using all available MR features yielded 100% sensitivity and 92% specificity. A Boolean 'AND' combination of an SUV max of 5.2 or greater with consent MR image interpretation improved sensitivity and specificity to 100%. Conclusion: In selected patients, 18 F-FDG PET/MR imaging can improve the noninvasive diagnosis and follow-up of cardiac masses.

In patients with reperfused acute myocardial infarction, the area of reduced FDG uptake correlates with the area at risk as determined with the ESA method and is localized in the perfusion territory of the culprit artery in the absence of necrosis, although the area of reduced FDG uptake largely overestimates the size of the infarct and the ESA-based area at risk.

A HFLCPP diet in combination with unfractionated heparin was successfully implemented for cardiac PET/MRI and resulted in a sufficient suppression of myocardial FDG uptake in 84% of patients.

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Background: In the present study, we sought to describe a procedure for the creation of co-registered positron emission tomography (PET) and magnetic resonance imaging (MRI) polar plots of cardiac PET/MRI examinations, validate the resulting plots against available standard methods in patients with myocardial infarction and provide examples that demonstrate the advantage of the novel approach over existing standards. Methods: Co-registered LGE and PET short-axis images were transformed into polar maps based on a radial sampling pattern. LGE was automatically detected using an automated thresholding algorithm (ATA). In 20 PET/MRI examinations in patients with acute myocardial infarction, agreement between manual LGE assessment and the ATA classification was calculated. Also agreement between MRI-segmentation based PET polar plots and standard PET polar plots (created with the Corridor4DM software package) was assessed. Results: No statistically significant difference in infarct sizes between manual and ATA segmentation was found (p = 0.12). Both methods were highly correlated (Pearson's r = 0.96, p < 0.01). Bland-Altman analysis revealed lower and upper limits of agreement of −4.7 g and 3.6 g. Agreement between MRI-segmentation based PET polar plots and standard PET polar plots was very high (mean kappa of 0.91 ± 0.10; p < 0.01 in all cases). In three additional patients with myocardial inflammation, the software successfully created polar plots that demonstrate How to cite this paper: Nensa, F., Poeppel, T.D., Tezgah, E., Heusch, P., Nassenstein, K., Forsting, M., Bockisch, A., Erbel, R. and 92the location and extent of pathologic tracer uptake in the left ventricular myocardium. Conclusion: A straightforward software approach for the creation of co-registered PET and MRI polar plots was described and successfully demonstrated in PET/MRI studies of myocardial infarction and inflammation.

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